一株嗜热地衣芽孢杆菌及其产高温淀粉酶的初步研究

从云南腾冲热海热泉中分离到23株产高温淀粉酶的菌株,选取酶活最高的一株菌株进行生长特征、16S rRNA基因测序及系统进化分析表明,该菌株为嗜热的地衣芽孢杆菌(Bacillus licheniformis),并命名为B.1icheniformis Tamy6。该菌株生长范围为37～70℃,最适生长温度为55℃。对该菌所产高温淀粉酶的性质研究表明:该酶在70℃具有最高催化效率,在98℃保温30min,仍有45%的活力,其最适反应pH为5.0。通过Native-PAGE酶谱分析表明菌株Tamy6的粗酶液中含有一种类型的淀粉酶。通过TLC分析水解淀粉产物表明,其产物主要为葡萄糖、麦芽糖及3～5个葡萄糖基的寡糖,说明菌株Tamy6所产淀粉酶为高温α-淀粉酶。

Studies on thermostable amylase from Bacillus licheniformis strain Tamy6

23 thermostable amylase producing strains were isolated from hot springs in Tengchong Rehai, Yunnan. Strain Tamy6 was selected for further study of its highest amylase activity. Physiology characteristics and 16S rRNA gene phylogenetic analysis showed this strain belonged to Bacillus licheniformis. The strain could grow at 37--70℃ and its optimal growth temperature was 55 ℃. The amylase from strain Tamy6 had the maximum activity at 70℃ and pH 5. 0, respectively. And after incubation at 98 ℃ for 30 min, 45 % residual activity of this amylase was detected. Native- PAGE analysis showed that there was only one type of amylase in the crude enzyme. TLC analysis demonstrated the amylase released glucose, maltose, and a range of other oligosaccharides from starch. The result indicated this amylase was a thermostable α- amylase.